About 85% of all batteries used commercially are alkaline batteries (dry cell batteries). These are currently essentially all land filled because current potential recycling processes for these batteries have high energy cost, capital costs, and processing costs which do not allow for sufficient economic incentive for the recovery of the valuable components of these batteries. Steel cased batteries contain about 26-65% steel, 4-10% alkaline electrolyte with 20-35% of mixed manganese oxides, 20-35% zinc hydroxide/oxide and some carbon. The size of the battery or ratio of casing to components determines the relative amount of steel casing to the zinc and manganese content. If these batteries are to be economically viable to be recycled, the zinc oxide/zinc compounds and the manganese oxides contained therein would have to be readily and efficiently isolated separately in high purity (>95%) and yield to maximize their value. In addition, the steel casings would also need to be isolated free of these other components for efficient recycle as scrap steel for steel production. There have been a number of processes described for processing and recycling these batteries. These processes range from pyro metallurgical ones in which the metal and manganese are recovered in an alloy and the zinc is partially recovered as impure in flue dust and requires much further processing by hydrometallurgical steps which require the total solution of the zinc and extensive chemical separation steps. There are some processes which attempt selective solution of the zinc and in the presence of considerable amount of the steel casing which in a mixed solution of manganese, steel and zinc now have to be separated with high purity requiring many processing steps and high energy.
The prior art has been unable to obtain high purity manganese dioxide at low-cost from the manganese oxides contained in these batteries. Consequently, the reuse of recovered manganese oxide has been with impurities. The use of impure MnO2 prepared from these batteries gives lower efficiency when used in new batteries.